A hot press method is known as one of the conventional methods of manufacturing metal-based composite materials. According to these methods, a laminate of intermediates, called a preform, such as: (1) a green tape {fiber is placed on a foil layer (packing foil) of a matrix metal and is adhered and fixed with an acrylic or styrene resin}, (2) a sprayed tape {in item (1) above, the fiber is covered and fixed with a sprayed matrix metal in place of the resin}, or (3) an impregnated wire preform (a fier bundle is immersed in molten matrix metal and the fiber bundle is infiltrated with the molten metal) is heated and pressed to prepare a composite material.
This heating/pressing method includes the solid phase press method for processign in a solid phase region of the matrix metal, and the liquid phase press method for processing in a solid/liquid phase coexisting region or a liquid phase region higher than the solidus of the matrix metal. In the former method, the heating temperature is relatively low, and degradation of the fiber due to the interfacial reaction between the fiber and matrix metal during forming is small. However, in order to obtain a composite material, high pressure processes are normally required, resulting in high equipment and manufacturing costs. In the latter method, forming can be performed with low-pressure processes, and advantages in respect to the equipment and manufacturing costs are obtained. However, the heating temperature during forming is high, and degradation of the fiber by the interfacial reaction and formation of a brittle phase at the interface tend to occur. As a result, the obtained composite material tends to have poor mechanical properties.
It is, therefore, an object of the present invention to provide a method of manufacturing a composite material with excellent mechanical properties, in which the interfacial reaction caused in the conventional liquid phase press method is suppressed.